Club Atlético San Martín was first established in September 1907. Usually known by the name San Martín San Juan, the team is nicknamed El Santo. Historically, San Martín San Juan have spent most of their existence outside of the top flight of Argentine football. The football team serves as a sub-section of a larger sporting club, which takes part in hockey and volleyball competitions, amongst others.

The side's biggest local rivals are Godoy Cruz and the two teams contest what has become known as the Clásico de Cuyo. Prior to the team's appearance in the national football league system, San Martín San Juan competed in regional competitions in the San Juan province. They are seen as the most successful side in the history of the regional championship, having won the most matches and the most titles.

To date, national silverware has been beyond the team's capabilities. However, in total, the club have had three stints in the top flight of Argentine football. The first came in the 1970 Nacional Championship, but San Martín San Juan finished 20th and were subsequently relegated. A second top flight season took place in 2007-08, before the side's most recent promotion ahead of the 2011-12 season. Perhaps the team's most significant top flight victory came in April 2013, when they ended a 16 game winless streak by thrashing Boca Juniors 6-1.

San Martín San Juan play their home matches at the Estadio Ingeniero Hilario Sánchez. The venue was inaugurated in 1951 and has undergone renovations several times in recent years, coinciding with the team's promotions to the top flight. Up until 2007, the stadium had a capacity of 13,000, but this was subsequently increased to make the stadium suitable for the Primera División. At present, it is able to hold up to 25,286 supporters.